While there is no definitive number of all animal species existing in the world, the closest estimation is approximately 8.7 million, over 1.5 million of which have been described. That's how many creatures there are to choose from when considering getting an animal tattoo. Sure, rotifers may not be a popular pick, but it is a legitimate one! No, but seriously, if you have any rare animal tattoos as such, please DM us.